{"id":"PYSEC-2026-3566","summary":"`datamodel-code-generator` vulnerable to code injection via unescaped carriage return in `--extra-template-data` `comment` field","details":"### Summary\n\n`datamodel-code-generator` is vulnerable to code injection when a developer passes an `--extra-template-data` file whose `comment` value contains a literal `\\r` (carriage return). The `comment` variable is rendered into a Python `#` comment in six built-in templates with **no** line-terminator escaping. Python's tokenizer treats a bare CR as a physical-line terminator (see [Python language reference — Physical lines](https://docs.python.org/3/reference/lexical_analysis.html#physical-lines)), so the comment ends at the `\\r` and the text after it is parsed as Python, including, when the CR is followed by suitable indentation, as a statement within the class body that follows on the next template line.\n\n### Details\n\nThe vulnerable templates each contain `# {{ comment }}` with no escaping:\n\n- `src/datamodel_code_generator/model/template/TypeAliasAnnotation.jinja2:12` and `:19`\n- `src/datamodel_code_generator/model/template/TypeAliasType.jinja2:12` and `:19`\n- `src/datamodel_code_generator/model/template/TypeStatement.jinja2:12` and `:19`\n- `src/datamodel_code_generator/model/template/pydantic_v2/BaseModel.jinja2:4`\n- `src/datamodel_code_generator/model/template/pydantic_v2/RootModel.jinja2:19`\n- `src/datamodel_code_generator/model/template/pydantic_v2/RootModelTypeAlias.jinja2:13`\n\nThe `pydantic_v2/BaseModel.jinja2:4` site is representative:\n\n```jinja2\nclass {{ class_name }}({{ base_class }}):{% if comment is defined %}  # {{ comment }}{% endif %}\n```\n\nWhen the developer-supplied extras file populates `comment` for a model, the value reaches the template via `DataModel.extra_template_data` (set in `src/datamodel_code_generator/model/base.py:736-742`) and Jinja2 interpolates it raw. None of the templates use `comment_safe`, `escape_docstring`, or any other line-terminator filter.\n\n### PoC\nComplete self contained POC is available at my secret gist: https://gist.github.com/thegr1ffyn/8ad6b8cb3cc2be9d3a0144aeb6896a3f\n\n### Impact\n\n- **Who's affected**: any developer or CI pipeline that runs `datamodel-codegen --extra-template-data \u003cfile\u003e` where the extras file is influenced by attacker-controlled input. Realistic scenarios include:\n  - Extras file generated from a third-party schema-annotation system.\n  - Extras file vendored from an upstream repository.\n  - Extras file produced by a script that merges multiple `comment` sources.\n  - Build pipelines that template the extras file from environment variables, ticket descriptions, or commit metadata.\n- **What it gains**: arbitrary Python code execution in the importer's process at `import` time.\n- **What it does NOT need**: the schema itself can be entirely benign; only the extras file needs to contain the malicious `comment`.\n- **What does block it**: not passing `--extra-template-data`, or rejecting extras files whose `comment` values contain `\\r`, `\\x0b`, or `\\x0c` before invocation.\n\n### Resolution\n\nThe fix normalizes `comment` values from built-in `--extra-template-data` before template rendering. Inline comments now convert CRLF, bare CR, vertical tab, and form feed into LF and prefix continuation lines with `# `, so attacker-controlled text stays inside the generated Python comment block.\n\n### Remediation\n\nUpgrade to `datamodel-code-generator` `0.60.2` or later.\n\nThis issue affects `datamodel-code-generator` versions `\u003e= 0.14.1, \u003c= 0.60.1` and is fixed in `0.60.2`.\n\nSubmitted by: Hamza Haroon (thegr1ffyn)","aliases":["CVE-2026-54654","GHSA-wjv6-jcfj-mf9r"],"modified":"2026-08-04T14:30:26.210993125Z","published":"2026-08-04T11:34:44.771231Z","references":[{"type":"WEB","url":"https://github.com/koxudaxi/datamodel-code-generator/security/advisories/GHSA-wjv6-jcfj-mf9r"},{"type":"WEB","url":"https://github.com/koxudaxi/datamodel-code-generator/commit/b73abb5cd703a50471b8950bbd3bd0b82ad71de7"},{"type":"PACKAGE","url":"https://github.com/koxudaxi/datamodel-code-generator"},{"type":"WEB","url":"https://github.com/koxudaxi/datamodel-code-generator/releases/tag/0.60.2"},{"type":"PACKAGE","url":"https://pypi.org/project/datamodel-code-generator"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-wjv6-jcfj-mf9r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54654"}],"affected":[{"package":{"name":"datamodel-code-generator","ecosystem":"PyPI","purl":"pkg:pypi/datamodel-code-generator"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.14.1"},{"fixed":"0.60.2"}]}],"versions":["0.14.1","0.15.0","0.16.0","0.16.1","0.17.0","0.17.1","0.17.2","0.18.0","0.18.1","0.19.0","0.20.0","0.21.0","0.21.1","0.21.2","0.21.3","0.21.4","0.21.5","0.22.0","0.22.1","0.23.0","0.24.0","0.24.1","0.24.2","0.25.0","0.25.1","0.25.2","0.25.3","0.25.4","0.25.5","0.25.6","0.25.7","0.25.8","0.25.9","0.26.0","0.26.1","0.26.2","0.26.3","0.26.4","0.26.5","0.27.0","0.27.1","0.27.2","0.27.3","0.28.0","0.28.1","0.28.2","0.28.3","0.28.4","0.28.5","0.29.0","0.30.0","0.30.1","0.30.2","0.31.0","0.31.1","0.31.2","0.32.0","0.33.0","0.34.0","0.35.0","0.36.0","0.37.0","0.38.0","0.39.0","0.40.0","0.41.0","0.42.0","0.42.1","0.42.2","0.43.0","0.43.1","0.44.0","0.45.0","0.46.0","0.47.0","0.48.0","0.49.0","0.50.0","0.51.0","0.52.0","0.52.1","0.52.2","0.53.0","0.54.0","0.54.1","0.55.0","0.56.0","0.56.1","0.57.0","0.58.0","0.59.0","0.59.1","0.60.0","0.60.1"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/datamodel-code-generator/PYSEC-2026-3566.yaml"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"}]}